Have reached the diagnostic limits of my Autel MaxiSys MS906BT. Need to acquire something with greater diagnostic capabilities; reading fault codes alone is no longer sufficient.

Currently, Mercedes-Benz USA's cheapest diagnostic equipment offerings include a J2534 passthru with a one year software package for $3,922, + tax, and a Xentry Diagnosis 4 Scope for $7653. Otherwise, a XENTRY Diagnosis Kit 4, with a 4 year software subscription, is $30,282.

The Chinese clones are substantially cheaper but how do you intelligently shop for such an item? Anything out there that has proven to be effective and reliable?

Any recommendations of where to look and what to consider?